Krzysztof Ozimek · 2026-06-30
The paper argues that comparing trading strategies by a single number over a whole backtest hides how they perform under different market conditions. Using 146 walk-forward folds on the S&P 500 (2002–2025), it models a risk-adjusted performance metric (Adjusted Information Ratio) for an SVM strategy versus buy-and-hold, conditioning the full distribution (mean, variance, shape) on volatility and momentum regimes. It finds that whether the SVM strategy beats buy-and-hold depends on the prevailing market regime.
Why it matters: The takeaway for practitioners is that a strategy's edge may be regime-dependent, so a single headline Sharpe/Information Ratio can be misleading. The proposed framework offers a more granular way to evaluate when a strategy tends to help versus hurt, which could inform regime-aware allocation or turning strategies on/off.
⚠ This is a backtest-only methodological study on one index and one SVM strategy, so results may not generalize or survive live trading and transaction costs.
Conventional comparisons of algorithmic trading strategies reduce each performance metric to a single number over the full backtest horizon, thereby discarding information about how performance varies with market conditions. This paper proposes a distributional framework that addresses this shortcoming. A walk-forward backtest of 146 out-of-sample folds on the S&P 500 (2002--2025) is used to compute the Adjusted Information Ratio ($IR^{\ast}$) for a polynomial Support Vector Machine strategy (SVMP) and a buy-and-hold benchmark (BH) in each fold. The resulting $IR^{\ast}$ sequences are modelled jointly via a Generalised Additive Model for Location, Scale and Shape (GAMLSS) with a Zero-Adjusted Gamma (ZAGA) response, with distributional parameters conditioned on market regime covariates: realised volatility and cumulative market momentum. Strategy comparison is conducted through (i) regime-specific differences in expected $IR^{\ast}$ ($ΔE$) and its variance ($ΔVar$), derived analytically from the fitted ZAGA parameters, and (ii) parametric bootstrap tests of three null hypotheses concerning $E(IR^{\ast})$, $Var(IR^{\ast})$, and their ratio, evaluated at six representative market regimes. The results demonstrate that the dominance relationship between SVMP and BH is conditional on market regime. The proposed GAMLSS/ZAGA framework constitutes a methodologically rigorous and practically interpretable alternative to conventional strategy evaluation.
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